The invention relates to the field of diagnostics and in particular to a painless collection of fluid for optical measurement of blood components. There are a variety of analytical systems for detecting analytes such as glucose, in which blood is collected from the patient and applied to a test carrier in order to then be measured in a measuring instrument separately from the blood collection. These measuring instruments may utilize optical detection as well as electrochemical detection. These systems in most cases have a test strip on which the patient must deposit a drop of blood.
A combination is described in U.S. Pat. No. 6,603,987 in which a needle array is used which is connected with a test strip. A disadvantage of this method is that it cannot be used for continuous measurement since the test strip can only be used for a single measurement. This means that the patient must prick himself several times daily with the needle array.
U.S. patent application number US 20030185384 describes the production of microneedles and the linkage of a needle array with a sensor element. An electrochemical detection element is disclosed which is connected to the needle array by means of a transfer medium (for example a hydrophilic porous material which takes up the liquid). This system also has the disadvantage that it cannot be used to continuously monitor the patient. This again leads to the disadvantage for the patient that he must prick himself several times daily.
As a result of the reagents used for the analysis as they are described in the prior art, the test element can only be used for one measurement since the reagents are consumed in the reaction with the analyte. This means that the patient has to exchange the test element for a new one after each measurement. In addition to the work required by the patient to change the test elements, another disadvantage is that the system can only be miniaturized to a limited extent if the system is to remain manageable for the patient.